Apparatus and method for coating bulk material

ABSTRACT

A coating apparatus and method are disclosed for coating tablets with a film, in which the tables transit through a drilled first container where they are coated, then exit the first container and are removed from a rotating element provided on the periphery of a plurality of removal members that are spaced angularly apart from one another, in which each removal member removes a quantity of tablets, raises the removed tables as far as a certain height and then discharges the tablets into a chute that conveys the tablets into a second rotating drilled container, with delicate transfer of the coated tablets from one container to the next.

BACKGROUND OF THE INVENTION

The invention relates to an apparatus and a method for coating bulkmaterial, in particular for coating material in the form of granules,pellets, tablets, pills, capsules, particles etc, with at least onelayer of coating material.

Specifically, but not exclusively, the invention can be applied to coatpharmaceutical products (for example tablets) or food products, inparticular to produce tablets coated with film.

It is known to form the coating of pharmaceutical tablets inside adrilled pan, with a circular or polygonal section, rotated on itslongitudinal axis in order to move the mass of the tablets, inside whichat least one gun is arranged that sprays the coating material.

It is also known to generate a flow of gas (treated air) that is forcedfrom the exterior to the interior of the pan, passing through the holesand the mass of the tablets, to perform drying, heating and coolingaccording to process needs.

Plants are known that work in batch mode, with a product loading step,in which the pan is filled with the desired quantity of tablets, aproduct coating step, and a discharge step until the pan is completelyemptied. Plants are also known that work in continuous mode, in whichthe product moves without interruption from a loading zone, where theproduct enters the pan, to a discharge zone.

In continuous mode, a stationary phase exists, in which the mass of theprocessed product is more or less constant (some enters the pan, some isprocessed, some exits) and two transition phases, a start or fillingstep, in which there is a transition from pan empty status to stationaryproduction status and another switching off or emptying step, in whichthe opposite occurs.

Patent publication US 2008/0193632 A1 shows an apparatus for coatingtablets in which a rotating drum has an inlet and an outlet for thetablets and in which a rotating adjustable weir partially obstructs theoutlet so as to maintain a bed of tablets in the drum at a set depth.

Patent publication US 2010/0080897 A1 shows an apparatus for continuouscoating of pellets that is dispensed along a channel that is vibrated tomaintain the pellets in a fluidized state.

Patent publication US 2012/121774 A1 shows an apparatus for coatingtablets in which the coating material is dispensed by spraying inside acontainer in a series of independently controlled zones, with dispensingdurations differing from one zone to another.

Patent publication US 2006/127532 A1 shows an apparatus for continuouscoating of pieces of rubber material that are conveyed through a firstrotating drum with a tilted axis in which a first coating material isapplied and which are then transferred, by a conveyor, to a secondrotating drum for the application of a second coating material.

Patent publication U.S. Pat. No. 5,721,012 shows an apparatus forcontinuous coating of bulk material that is introduced in a firstrotating drilled drum with a tilted rotation axis, where it receives acoating solution, to then be transferred to a second rotating drumthrough a conduit.

Patent publication U.S. Pat. No. 5,010,838 shows an apparatus forcontinuous coating of edible cores, with two rotating drums arranged oneafter the other and a conveyor for continuously conveying the cores fromthe discharge of the first drum to the inlet of the second drum.

Patent publication U.S. Pat. No. 4,465,017 shows an apparatus forcoating seeds with two serially arranged rotating drums, wherein eachdrum has outlet holes provided with manual valves to regulate the flowof the seeds.

Patent publication U.S. Pat. No. 5,501,874 shows a coating apparatusinto which the granular material is dropped, the coating material issprayed onto the falling material, the drying gas flows upwards, thedropped material is taken to an upper portion of apparatus.

Patent publication U.S. Pat. No. 5,433,964 shows an apparatus forcoating food with an edible substance in a rotating drum, lifting andseparating the food by pins arranged radially inside the drum.

Various aspects of the prior art are improvable.

Firstly, it is desirable to build coating systems provided with greaterflexibility and versatility, i.e. that is able to be easily and rapidlyadapted to processes with different features, for example with differentflow rates of the product to be processed, or different process times,etc.

Secondly, it is desirable to increase the level of ergonomics of theknown coating systems, in particular by reducing the effort that theoperator makes to manage the process, which often occurs in plans ofsignificant complexity and overall dimensions, with the need for theoperator to keep under control a space of considerable extent bothhorizontally and vertically.

Another problem of the prior art is to ensure correct movement of theproduct, in particular in the transition phases, for example to ensuresufficient dwell time of the product in the start or filling step and/ora rapid outflow of the product in the step of switching off or emptying.

SUMMARY OF THE INVENTION

One object of the invention is to devise a coating apparatus that isable to solve one or more of the aforesaid problems of the prior art.

One object of the invention is to devise a coating method that is ableto solve one or more of the aforesaid drawbacks of the prior art.

One advantage is to make available a coating apparatus and/or method ofsignificant flexibility and versatility.

One advantage is to realize a coating apparatus and/or method easily andrapidly adaptable to processes with differing features, in particular atthe variation of the flow rate of the product to be processed or of theprocess time.

One advantage is to permit modular construction of a coating apparatus,so that it is possible to obtain great flexibility and versatility byvarying the number and/or the arrangement of the modules used.

One advantage is to improve the ergonomics of the coating process, inparticular owing to the fact that the operator can manage the process bymaintaining a relatively limited area under control.

One advantage is to permit the product inlet and outlet to be on thesame side of the apparatus and with a relatively reduced difference inlevel between inlet and outlet.

One advantage is to obtain a particularly delicate movement of the bulkmaterial, in particular in a step of transferring the bulk material froma first rotating container to a second rotating container.

One advantage is to permit simple and effective regulation of the flowof the bulk material that has to be coated.

One advantage is to provide a coating apparatus provided with relativelyreduced overall dimensions, both in a vertical (height) direction and ina horizontal (width and length) direction.

One advantage is ensuring correct handling of the product, in particularensuring sufficient duration of the product in the start step and/or arapid outflow of the product during the switching-off step.

One advantage is providing an apparatus and/or a method that is suitablefor continuous production or for discontinuous (batch) production.

One advantage is to give rise to a coating apparatus that isconstructionally simple and cheap.

Such objects and advantages and still others are achieved by anapparatus and/or by a method according to one or more of the claims setout below.

In one embodiment, a coating apparatus, which is suitable for coatingbulk or loose material in the form of granules, pellets, tablets, pills,capsules, particles, etc, comprises a first rotating container where thebulk material is coated with coating material, a (rotating) movableelement arranged for conveying the coated bulk material coming from thefirst container, and a second rotating container that receives the bulkmaterial coming from the movable element, in which the movable elementis provided (on the periphery) with a plurality of removing portions(each of which is shaped so as to define at least one cavity or achamber, for example in shape of a container, drawer, socket, etc)angularly spaced apart from one another, each of which comprises amovable wall (for example in the form of a blade or door), in whichduring movement (rotation) of the movable element each removal portionremoves a quantity of bulk material (exiting the first container) andlifts the quantity of bulk material up to a certain height, after whichthe movable wall opens and the bulk material exits the removal portionand then enters (for example passing on a chute) the second rotatingcontainer where it can be shaped and arranged to be further processed.

Each removal portion is movable (cyclically, for example along acircular trajectory) from a lower removal zone, where it collects aquantity of bulk material coming from the first container, to an upperrelease zone, in which it discharges the material that is then conveyedto the second container.

Each removal portion may comprise a tilted side so that, when themovable wall opens, the exit of the bulk material from the removalportion is promoted by the force of gravity. The exit of the bulkmaterial from the removal portion, when the movable wall opens, may bepromoted by a centrifugal force due to the movement (rotation) of the(rotating) movable element and/or by an aerodynamic force due to themovement of air generated by the opening of the movable wall. It ispossible to provide for the use of an expelling device that is suitablefor promoting the exit of the bulk material from the removal portion, inparticular a mechanical device comprising, for example, at least onepusher, a piston, a lever mechanism, etc.

The opening of the movable wall may be guided by cam means, for examplecomprising a fixed cam profile engaging with a plurality of slidingpins, each of which is associated with a respective movable wall.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood and implemented with reference tothe attached drawings that illustrates embodiments thereof by way ofnon-limiting example, in which:

FIG. 1 is a side view of a diagram of a first embodiment of a coatingapparatus made according to the invention;

FIG. 2 is a view from the right of FIG. 1;

FIG. 3 is a top perspective view of a second embodiment of a coatingapparatus made according to the invention;

FIG. 4 is the view of the apparatus of FIG. 3 with some parts removed tohighlight others better;

FIG. 5 is a section on a vertical plane of the first rotating containerof the apparatus of FIG. 3;

FIG. 6 shows an enlarged detail of FIG. 5;

FIGS. 7 to 10 are frontal views in a vertical elevation of someoperating steps of a removal portion of the apparatus of FIG. 3 from thebulk material removal phase to the bulk material discharge phase;

FIG. 11 is a perspective view of the zone of the apparatus of FIG. 3 inwhich the bulk material is transferred from the exit of the firstrotating container to the inlet of the second rotating container;

FIG. 12 is a frontal view in a vertical elevation of the zone of FIG.11;

FIG. 13 is a frontal view in a vertical elevation of a third embodimentof a coating apparatus to show schematically the arrangement of theprocess gas inlet and outlet;

FIG. 14 is a perspective view of one embodiment of a rotating elementthat is used in a coating apparatus made according to the invention;

FIG. 15 shows a cross section of the element of FIG. 14 according to aplane of normal section on the axis of the element;

FIG. 16 shows a longitudinal section of the element of FIG. 14 accordingto a section plane passing through the axis of the element.

DETAILED DESCRIPTION

With reference to the aforesaid figures, identical elements of differentembodiments have been indicated for the sake of greater clarity andsimplicity by the same numbering. Overall, by 1 a coating apparatus hasbeen indicated that is usable for coating bulk or loose material, inparticular material in the form of granules, pellets, tablets, pills,capsules, particles, etc.

The apparatus 1 may be used, for example, to coat pharmaceuticalproducts (for example tablets) and/or food products. The coating maycomprise at least one layer of coating material such as, for example, acoating of polymer film that is suitable for coating pharmaceuticaltablets. The apparatus 1 may be used, in particular, to produce tabletscoated with film.

The coating apparatus 1 comprises a first container 2 that can receiveand discharge bulk material M. The first container 2 may be of tubularshape, for example with a circular or polygonal section. The firstcontainer 2 may rotate (around a first rotation axis X1) to promote themovement of the bulk material M. The first container 2 may rotate, forexample, around its own longitudinal axis.

The first container 2 may comprise a first inlet 3 and a first outlet 4of the bulk material M. The first inlet 3 and the first outlet 4 arearranged at two opposite ends of the first container 2. The firstcontainer 2 may rotate with a first horizontal or tilted rotation axisto promote the mixing of the bulk material and/or the transit of thebulk material from the first inlet 3 to the first outlet 4. The tilt ofthe first container 2 may be adjustable.

It is possible, as in these embodiments, for at least one part of thefirst container 2 to be permeable to a process gas (treated air) toprocess the bulk material M in the first container 2. In particular, thefirst container 2 may be drilled to permit the process gas to passthrough, retaining the bulk material.

The coating apparatus 1 may comprise, in particular, process gassupplying means (for example of known type) configured for supplying thegas through the first container 2 and thus through the bulk material Mcontained in the first container 2. The process gas may be suitable, inparticular, for drying, heating or cooling the bulk material, or forperforming other types of treatment.

The process gas may, as in this embodiment, enter or exit the front endof the apparatus (for example on the side of the first inlet 3 or on theside of the first outlet 4). The apparatus may comprise, in particular,an air inlet 23 and an air outlet 24 situated (for example on a casing25 that encloses the first container 2) in opposite (for examplediametrically opposite) positions with respect to the rotation axis ofthe first container 2. In this embodiment the air inlet 23 and the airoutlet 24 are arranged obliquely (in particular at 45°), i.e. animaginary line that joins the air inlet 23 and the air outlet 24 isoblique, forming an angle (of about 45°) with a vertical axis passingthrough the rotation axis of the first container 2. In particular, (withreference to FIG. 13) the two openings (i.e. the air inlet 23 and theair outlet 24) are arranged on the two opposite lateral sides of thefirst container 2, one higher up and the other lower down, with a settilt with respect to the rotation direction of the first container 2, insuch a manner that the higher opening is arranged on the part of a sideof the first container 2 that rotates downwards and the lower opening isarranged on the opposite side, i.e. on the part of a side of the firstcontainer 2 that rotates upwards. In this specific embodiment, the airinlet 23 is situated at the top and the air outlet 24 is situated at thebottom. In operation, the flow of process gas (treated air) is pushed ina forced manner from the outside to the inside of the drilled firstcontainer 2 and then from the inside to the outside, passing through theholes and the mass of the tablets.

The coating apparatus 1 may comprise, as in these embodiments, a supplyportion A arranged to receive the bulk material M from the outside anddirect the bulk material to the first inlet 3 of the first rotatingcontainer 2. The supply portion A (for example of known type) may befixed and arranged contiguously to the end of the first container 2where the first inlet 3 is situated.

The coating apparatus 1 comprises a first dispensing device 5 (forexample of known type) for dispensing coating material on the bulkmaterial M contained in the first container 2. The first dispensingdevice 5 may comprise, in particular, one or more nozzles arranged(aligned) inside of the first container 2 to spray the coating material.

The coating apparatus 1 comprises a second container 6 arranged seriallydownstream of the first container 2. The second container 6 may be oftubular shape, for example with a circular or polygonal section. Thesecond container 6 may be shaped and arranged to receive the bulkmaterial M coming from the first container 2 and to discharge the bulkmaterial M, for example to possible subsequent processes to be performedon the material. The second container 6 may rotate (around a secondrotation axis X2) to promote the movement of the bulk material M in thesecond container 6. The second container 6 may rotate, for example,around its own longitudinal axis.

It is possible, as in this embodiment, for at least one part of thesecond container 6 to be permeable to a process gas (treated air) toprocess the bulk material M in the second container 6. In particular,the second container 6 may be drilled to permit the transit of theprocess gas but not the transit of the bulk material M.

The coating apparatus 1 may comprise, in particular, process gassupplying means configured for supplying the process gas through thesecond container 6 and thus through the bulk material M contained in thesecond container 6. The process gas may be suitable, in particular, fordrying, heating or cooling the bulk material, or for performing othertypes of treatment.

The second container 6 may comprise a second inlet 7 and a second outlet8 of the bulk material M. The second inlet 7 and the second outlet 8 canbe arranged at two opposite ends of the second container 6. As FIGS. 11and 12 show, with the second container 6 a supply portion 15 (fixed,arranged coaxially to the second container 6 and contiguously to the endof the second container 6 that has the second inlet 7) may be associatedthat is suitable for guiding the entry of the material. The secondcontainer 6 may rotate around a second horizontal or tilted rotationaxis to promote mixing of the bulk material M and/or the transit of thebulk material M from the second inlet 7 to the second outlet 8. The tiltof the second container 6 may be adjustable.

The coating apparatus 1 may comprise, as in these embodiments, adischarge portion D (shown in FIG. 2) arranged to receive the bulkmaterial M that exits from the second outlet 8 of the second rotatingcontainer 6 and to discharge the bulk material M to the outside. Thedischarge portion D (for example of known type) may be fixed to andcontiguous with the end of the second container 6 where the secondoutlet 8 is situated. The discharge portion D may comprise a conveyor ofthe same type as the conveyor 10.

The coating apparatus 1 may comprise, as in this embodiment, a seconddispensing device 9 (for example of known type) for dispensing coatingmaterial (that may be the same type of material dispensed by the firstdispensing device 5 in the first container 2 or a material of differenttype) onto the bulk material M contained in the second container 6. Thesecond dispensing device 9 may comprise, in particular, one or morenozzles arranged (aligned) inside the second container 6 to spray thecoating material.

The first inlet 3 of the first container 2 and the second outlet 8 ofthe second container 6 (thus like the supply portion A and the dischargeportion D) are arranged on the same side of the apparatus, in particularon a front side where an operator workstation is situated. In otherembodiments, it is possible to load the bulk material on a behind orrear side, transfer the material to an opposite, frontal or forward side(operator side) and then discharge the material onto the behind or rearside.

In this specific embodiment, the bulk material M in transit in the firstcontainer 2 from the first inlet 3 to the first outlet 4 moves in acertain direction, whereas the bulk material M in transit in the secondcontainer 6 from the second inlet 7 to the second outlet 8 moves in adirection substantially opposite the aforesaid direction in the firstcontainer 2.

The coating apparatus 1 comprises conveying means arranged to convey thebulk material from the first container 2 to the second container 6.

Such conveying means may comprise, in particular, a conveyor 10configured for removing at least one part of the bulk material M exitingthe first container 2. The conveyor 10 may be configured, in particular,for removing the bulk material M at a certain (lower) level and thenlift the bulk material M to a higher level, to then discharge the bulkmaterial M to the second container 6. In other embodiments, anotherconveyor, identical to the conveyor 10, may be applied, if necessary, tothe discharge of the second container 6, i.e. near the second outlet 8,to remove at least one part of the bulk material M exiting the secondcontainer 6.

The conveyor 10 may comprise, in particular, at least one rotatingelement 11 that rotates around a rotation axis X one or more removalportions 12 each of which is arranged to remove bulk material M from theaforesaid lower level and then lift the bulk material M up to theaforesaid higher level. Each removal portion 12 is shaped so as todefine a containing chamber containing a quantity of bulk material M.

The rotating element 11 may rotate around a rotation axis X that isdistinct and driven independently of the first rotation axis X1 aroundwhich the first container 2 rotates. The rotation axis X of the rotatingelement 11 may be, in particular, but not necessarily, parallel (orcoaxial, as in this specific embodiment) to the first rotation axis X1of the first container 2.

Each removal portion 12 is configured for performing, at each rotationof the rotating element 11, a removal of a quantity of bulk material M.In the specific case the rotating element 11 may comprise a plurality ofremoval portions 12 that are arranged on a periphery of the rotatingelement 11 angularly spaced apart from one another.

In the embodiment disclosed here, the conveyor 10 comprises at least oneremoval portion 12 arranged on a rotating element 11, so that theremoval portion 12 is movable along a circular trajectory.

It is possible to provide other embodiments (which are not illustrated)in which the conveyor 10 comprises at least one removal portion 12 thatis movable along a closed loop path, which is not necessarily circular(for example defined by a flexible conveying element, such as a belt ora chain), in which it may adopt at least one lower position, in which itremoves the bulk material M from a lower level, and at least one upperposition, in which it discharges the bulk material M to a higher level.In other embodiments, it is possible for each removal portion to becommanded to perform an open trajectory, in particular with an outwardand return motion, in which the removal operation may be performed(only) during the outward or during the return motion.

The rotating element 11 may be arranged, as in this embodiment, oppositeand contiguously to an end of the first container 2 from which the bulkmaterial M exits. The rotating element 11 may comprise, as in thisembodiment, a rotating cylindrical body (coaxial with the firstcontainer 2) that supports the various removal portions 12.

Each removal portion 12 may be, as in this embodiment, in the shape of acontainer (drawer, socket, spoon, etc) configured for containing aquantity of bulk material M. Each removal portion 12 may comprise atleast one (movable) wall, for example in the shape of a blade, thatbounds at least in part the containing chamber of the bulk material M.

The rotating element 11 may rotate around the rotation axis Xselectively in a first rotation direction and in a second rotationdirection that is opposite to the first one.

The movable wall 13 may be tilted so as to remove the bulk material Mfrom the aforesaid lower level when the rotating element 11 rotates in afirst rotation direction (that is the same as the rotation direction ofthe first container 2 around the first rotation axis X1).

The rotating element 11 (cylinder) may include, for example as in FIGS.5 and 6, a plurality of blades 22 arranged in front of the removalportions 12, with reference to the advancement direction of the bulkmaterial (tablets). The blades 22 are arranged circumferally around theaxis of the rotating element 11, forming a crown of blades that operateon the bulk material. The blades 22 may be tilted with respect to therotation axis of the element 11. The blades 22 are shaped and arrangedin such a manner as to push back or facilitate the flow of the material,according to the rotation direction of the element 11.

In particular, the blades 22 are tilted so as to push back at leastpartially the bulk material M to the inside of the first container 2when the rotating element 11 rotates in a second rotation direction(opposite the first rotation direction and opposite to the rotationdirection of the first container 2 around the first rotation axis X1).By considering the flow of the bulk material M that exits the firstcontainer 2, the material first meets the system of blades 22, that issuitable for obstructing or facilitating the flow of the materialaccording to the rotation direction, then meets the system with theremoval portions 12 (containing chambers), which has similar behaviouras each removal portion 12, by virtue of the shape thereof, does notretain the material when the element 11 rotates in a direction oppositethe first container 2 and, vice versa, removes the material when theelement 11 rotates in the same direction as the first container 2.

Each removal portion 12 may comprise, in particular, at least oneremoval opening of the bulk material M and at least one dischargeopening of the bulk material M. The removal opening may be arranged, asin this embodiment, with a prevalently axial orientation (facing theinside of the first container 2). The discharge opening may be arranged,as in this embodiment, with a prevalently radial (outwardly facing)orientation. The terms “axial” and “radial” must be understood to referto the rotation axis X of the rotating element 11, or to the firstrotation axis X1 of the first container 2.

The aforesaid wall 13 of the removal portion 12 may act as a blade, i.e.as a tool for removing the bulk material M, and may comprise a flatbody, possibly curved or concave.

The aforesaid (movable, in particular closable and openable) wall 13 ofthe removal portion 12 may act, substantially, as a shutter member withthe possibility of adopting a closed position in which it closes thedischarge opening, when the removal portion 12 is in the lower level,and an open position in which the discharge opening opens, when theremoval portion is in the upper level.

The coating apparatus 1 may comprise, in particular, driving means, forexample of the cam type, arranged to move the movable wall 13 (shutter)between the closed and open positions. The wall 13 may be movablebetween the closed and open positions by rotating around a fulcrum 14.In particular, the movement of the movable wall 13 may be guided by cammeans comprising a fixed cam profile engaged with a pin that is slidableand integral with the movable wall 13. During the rotation of therotating element 11, the coupling between the pin and the cam profilecauses the opening movement (rotation around the fulcrum 14) of themovable wall 13 in the discharge zone of the bulk material M at theaforesaid upper level, and the closing movement of the wall 13 once thebulk material M has been discharged. The cam profile may be engaged witha plurality of pins, one for each removal portion 12.

Each removal portion 12 may comprise a side with a (fixed) wall 16tilted in such a manner that, when the movable wall 13 opens (at theupper position in the release zone), the exit of the bulk material Mfrom the removal portion 12 is promoted by the force of gravity. Theexit of the bulk material M from the removal portion 12, when themovable wall 13 opens, may be promoted by a centrifugal force due to themovement of air generated by the opening of the movable wall 13. The(fixed) wall 16 bounds the containing chamber of the bulk material M.

The conveying means may comprise, in particular, at least one chute 17arranged to convey the bulk material M coming from the conveyor 10 tothe second container 6 (in particular through the supply portion 15arranged on the second inlet 7). The chute 17 may be arranged to receivethe bulk material M discharged from the various removal portions 12 whenthe latter reach the release zone of the material at the aforesaid upperlevel.

The coating apparatus 1 comprises motor means 18 for driving theconveyor 10, in particular for rotating the rotating element 11. Thecoating apparatus 1 may further comprise first motor means 19 forrotating the first container 2 and second motor means 20 for rotatingthe second container 6. The motor means 18 of the conveyor 10 may bedistinct from and adjustable independently of the first motor means 19and of the second motor means 20. The first motor means 19 may bedistinct from and adjustable independently of the second motor means 20.

The first container 2 may comprise, as in this embodiment, a series oftilted ridges 21 (in other embodiments the ridges could also not betilted) that protrude radially inside from the inner surface of thefirst container 2 (in particular arranged near the first outlet 4) andthat act as deflectors or blades for moving the bulk material M.

In FIGS. 14 to 16 another possible embodiment of the rotating element 11is illustrated that comprises, in this specific case, a plurality ofgrooves 26 arranged on an inner wall of the element 11. The grooves 26can be arranged circumferally around the second rotation axis X. Eachgroove 26 defines a bulk material M conveying channel. Each groove 26may extend along a circumference arc that lies on a plane that is tiltedin relation to the second rotation axis X. It is possible, for example,that for each groove 26, the plane on which the groove lies is tilted inrelation to the second rotation axis X by an angle that is greater than45° and less than 90°, so as to regulate the exit of bulk material Mfrom the first container 2.

The operation of the apparatus 1 is disclosed below.

In this specific embodiment, the coating apparatus 1 works continuously,so that there is a stationary work step in which the bulk material Mmoves without interruptions, from a loading zone where the bulk materialM enters the first container 2 (enters through the first inlet 3, firstpassing through the fixed supply portion A), to a final discharge zonewhere the bulk material M exits the second container 6 (exits throughthe second outlet 8 to then be discharged outside by passing through thefixed discharge portion D, or, in other embodiments, passing through aconveyor identical to the conveyor 10). In the stationary productionstep, the mass flow rate of the bulk material M that traverses theapparatus 1 is (approximately) constant, so that the flow rate ofmaterial that enters the supply portion A and thus the first container 2is (approximately) the same as the flow rate that exits the secondcontainer 6 and thus the discharge portion D.

In stationary operation, the bulk material M (tablets) is introduced (ina known manner) into the first container 2 through the first inlet 3.The first container 2 rotates continuously at a desired rotation speed(controlled by programmable electronic control means) around the firstrotation axis X1 so as to handle (convey and mix) the bulk material M,whilst the first dispensing device 5 sprays the coating material ontothe bulk material M. The continuous rotation of the first container 2promotes the transit of the bulk material M towards the first outlet 4of the first container 2. A flow of process gas (treated air) is pushedin a forced manner from the outside to the inside and then from theinside to the outside, passing through the holes and the mass of thetablets, both for the first container 2, and for the second container 6.

In the stationary phase, the rotating element 11 rotates in a givenrotation direction around the rotation axis X, in particular in arotation direction in accordance with the rotation direction of thefirst container 2, at a continuous rotation speed (regulated by theprogrammable electronic control means) that may be different from (forexample lower than) the (continuous) rotation speed of the firstcontainer 2, set at a value that is such as to maintain correctly thestationary condition, on the basis of the flow rate of the bulk materialM, at the dwell time of the bulk material M in the first container 2, atthe flow rate of the coating material, and at the other (known) processparameters.

During the rotation of the rotating element 11, each single removalportion 12 collects (with the movable wall 13 in closed position), ateach revolution of the rotating element 11, a certain quantity of bulkmaterial M, exiting the first container 2 at the lower level (in theremoval zone), retains the bulk material M by lifting the bulk materialM as far as upper level, where the movable wall 13 receives the openingcommand (owing to the cam means) to enable the bulk material M (in therelease zone) to be discharged. The bulk material M is dischargedtowards the chute 17 by a combined effect of centrifugal force, force ofgravity and aerodynamic force.

In FIGS. 7 to 10 four moments are illustrated in sequence of the liftingstep of the bulk material M starting from the removal zone (lower level)until to the release zone (upper level).

After which the bulk material M, which has been discharged from theremoval portion 12 in the release zone, slides on the chute 17 until itenters the second container 6 (through the supply portion 15 and thesecond inlet 7), then transits in the second container 6 where it can befurther processed (for example sprayed with coating material by thesecond dispensing device 9), in order to then exit the second container6 (through the second outlet 8) and lastly be discharged outside throughthe discharge portion D.

There are also two transitional work steps, a start or filling step,starting from a state in which the containers 2 and 6 are empty untilthe stationary production state, and a switch-off or emptying step, inwhich the opposite occurs.

In the initial transition phase, the rotating element 11 may rotatearound the rotation axis X in a rotation direction that is opposite therotation direction of the stationary phase, in particular a rotationdirection that is opposite the rotation direction of the first container2 around the first rotation axis X1, so as to obstruct the exit of thebulk material M and promote (accelerate) reaching a desired level ofmaterial inside the first container 2. Whilst the level of the bulkmaterial M increases in the first container 2, the rotation speed of therotating element 11 may be regulated (by the programmable electroniccontrol means) so as to move the material in the desired manner. It ispossible to regulate the rotation of the rotating element 11 by passinggradually from one rotation direction (opposite the first container 2)to the opposite rotation direction (in the same direction as the firstcontainer 2), checking the first container 2 so that it always rotatesin the same direction. Once the desired conditions have been achieved(for example the desired quantity of bulk material M in the firstcontainer 2), the stationary phase can start. During this initial starttransition phase, the conveyor 10 promotes filling of the firstcontainer 2, obstructing and/or stopping the transfer downstream of thebulk material M, in particular owing to the reverse rotation of therotating element 11.

The rotating transfer element 11 may be provided, as in this embodiment,with a plurality of tilted blades 22 for promoting the transfer of thebulk material M when the rotating element 11 rotates in one direction(in the same direction as the rotation of the first container 2) and forpushing back the bulk material M when the rotating element 11 rotates inthe opposite direction (in the opposite direction to the rotation of thefirst container 2).

In the final transition phase, the rotating element 11 may rotate with arotation direction in the same direction as the rotation direction ofthe first container 2 and at a rotation speed that is greater than orthe same as that which it had in the stationary phase, so as tofacilitate/accelerate the emptying of the first container 2, alsowithout damaging the bulk material M.

The ratio of the rotation speeds of the rotating element 11 and of thefirst container 2 may be variable, changing from the initial transitionphase to the stationary phase and thus changing from the stationaryphase to the final transition phase, and may be programmed in theelectronic control means of the coating apparatus 1.

The invention in question permits a very delicate transfer of the bulkmaterial (pharmaceutical tablets or other items) from one rotatingcontainer to the next one, preserving the bulk material that has justbeen processed (coated) with significant efficacy.

The bulk material is transferred by making it perform a movement that atleast in part comprises a lifting or raising of level, from the outletof a rotating container and before reaching the next rotating container.This lifting, enables, amongst other things, the two rotating containersto be arranged at two positions that are not very different from oneanother (or are even at the same position), thus limiting the verticaldimension of the apparatus overall. It is possible, in other embodimentsthat are not illustrated, that the second rotating element (downstream)is arranged at a position that is higher than the first rotating element(upstream).

The inlet of the material to be processed into the apparatus (fixedsupply portion A and first inlet 3 of the first rotating container 2)and the outlet of the processed material from the apparatus (secondoutlet 8 of the second rotating container 6 and fixed discharge portionD) are arranged on the same (front) side of the apparatus, withconsequent case and practicality in the control of the apparatus by anoperator, although in other embodiments the inlet of the material to beprocessed and the outlet of the processed material can be arranged ondifferent sides of the apparatus.

Further, in this specific embodiment, the level (in a verticalelevation) of the inlet of the material to be processed and the level ofthe outlet of the processed material have a relatively reduceddifference; in other embodiments (which are not illustrated) thedifference in level between the inlet and outlet could be even morereduced. This minimum difference in level enables the facility andpracticality of the control for an operator to be further improved.

The coating apparatus 1 disclosed above is designed for continuousproduction, but it is also possible to provide coating apparatuses thatare suitable for discontinuous (“batch” mode) production. In anapparatus that is suitable for working in “batch” mode, for eachrotating container a work cycle will be provided that comprises a bulkmaterial loading step in which the rotating container is filled with thedesired quantity of material, a work step in which the aforesaidquantity of material is coated with the coating material remaininginside the container, and a discharge step in which the rotatingcontainer is emptied completely.

Also in “batch” mode, a conveyor or lifter may be arranged between thefirst container and the second container in such a manner as to maintainor raise the level of the bulk material that exits the first container,during the step of transferring the material from the first to thesecond rotating container.

It has been seen that the apparatus in question enables the bulkmaterial that exits a rotating container to be removed, retained andraised in level before introducing the material into the next rotatingcontainer. This enables an apparatus to be made that comprises severalserially arranged rotating containers and has significant operatingversatility and flexibility, relatively compact dimensions and goodergonomics. These features may be improved further by arranging, assaid, another conveyor, similar to the conveyor 10, also at the secondoutlet 8 (outlet of the second container 6).

The aforesaid conveyor or lifter that raises the level of the materialcan be useful during the start step of the apparatus, in which theapparatus is empty and starts to receive the flow of material to becoated, to stop or temporarily slow this flow of materials so as to forma minimum layer of material, which is a necessary condition for thestart of the coating step (spraying of the coating material). This maybe achieved, as seen, by moving the conveyor or lifter in a directionopposite the movement direction that will be used in the stationaryphase.

The coating apparatus may be constructed in a modular manner, bycombining appropriately the number and/or the arrangement of therotating containers and of the conveying means that transfer the bulkmaterial from one container to the other, easily adapting the apparatusto different productive needs.

In the embodiment disclosed here, the coating apparatus 1 comprises tworotating containers (first and second containers 2 and 6) arrangedserially one after the other. It is possible, in other embodiments thatare not illustrated, to provide apparatuses comprising a differentnumber (three, four or more) of rotating containers arranged seriallyone after the other. The bulk material M may be conveyed from the secondcontainer 6 to a third rotating element, lifting the bulk materialexiting the second container 6 from a lower level to an upper level sothat the bulk material M reaches the third container; the same may occurfrom the third to a fourth container, and so on.

The possibility of arranging several containers serially to process thebulk material enables a modular apparatus to be created that has greatflexibility and versatility, that is easily adaptable to varying of theprocess parameters, such as for example the flow rate of the bulkmaterial to be processed, the dwell time of the bulk material in theapparatus, the type of bulk material to be coated or of coatingmaterial, etc.

1. Coating apparatus (1), comprising: a tubular rotating first container(2) arranged to receive and discharge bulk material (M) and to rotateabout a first rotation axis (X1) in such a way as to promote the movingof the bulk material within said first container (2); a first dispensingdevice (5) for dispensing coating material on the bulk material (M) insaid first container (2); a tubular rotating second container (6)arranged to receive bulk material (M) coming from said first container(2) and to rotate in such a way as to promote the moving of the bulkmaterial (M) within said second container (6); conveying means arrangedto convey the bulk material (M) from said first container (2) towardssaid second container (6); characterized in that said conveying meanscomprises at least one conveyor (10) configured to remove the bulkmaterial (M) from said first container (2) from a lower height, raise itto an upper height and discharge it towards said second container (6),wherein said conveyor (10) comprises at least one rotating element (11)which rotates about a second rotation axis (X), the rotation of therotating element (11) being independently controllable with respect tothe rotation of the first container (2).
 2. Apparatus according to claim1, wherein said second rotation axis (X) is parallel or coaxial withrespect to said first rotation axis (X1).
 3. Apparatus according toclaim 1 or 2, wherein said rotating element (11) is arranged in front ofan outlet end of said first container (2) from which the bulk materialis released.
 4. Apparatus according to any one of the preceding claims,wherein said rotating element (11) is able to selectively rotate in afirst direction of rotation and in a second direction of rotation thatis opposite the first direction of rotation, said apparatus (1)comprising control means configured to control said rotating element(11) according to operating modes comprising: (i) stationary operationin which said rotating element (11) rotates in said first direction ofrotation; (ii) filling initial transitional operation in which saidrotating element (11) rotates in said second direction of rotation;(iii) emptying final transitional operation in which said rotatingelement (11) rotates in said first direction of rotation at a rotationspeed greater than or equal with respect to the stationary operation. 5.Apparatus according to any one of the preceding claims, wherein saidconveyor (10) comprises at least one removal portion (12) that ismovable along a closed loop path wherein it can assume at least onelower position, in which it removes the bulk material (M) from saidlower height, and at least one higher position, in which it dischargesthe bulk material (M) at said upper height.
 6. Apparatus according toclaim 5, wherein said at least one removal portion (12) comprises atleast one removal opening of the bulk material and at least onedischarge opening of the bulk material.
 7. Apparatus according to claim6, wherein said removal portion (12) rotates about the second rotationaxis (X), said removal opening being arranged with a prevalently axialand/or radial orientation, where axial and/or radial is intended withreference to said second axis of rotation (X).
 8. Apparatus according toclaim 6 or 7, wherein said removal portion (12) comprises a movable wall(13) that is able to assume a closing position in which it closes saiddischarge opening when the removal portion (12) is in said lowerposition, and an opening position in which it opens said dischargeopening when the removal portion (12) is in said upper position. 9.Apparatus according to any one of the preceding claims, wherein saidrotating element (11) on an inner wall comprises a plurality of grooves(26) arranged circumferentially about the second axis of rotation (X),each groove (26) defining a channel conveying bulk material (M). 10.Apparatus according to claim 9, wherein each of said grooves (26)extends along a circumferential arc lying on a plane that is inclinedwith respect to said second axis of rotation (X), preferably of an anglegreater than 45° and lower than 90°, so as to regulate the release ofbulk material (M) from said first container (2).
 11. Apparatus accordingto any one of the preceding claims, wherein said conveying meanscomprises at least one chute (17) arranged to convey the bulk material(M) coming from said conveyor (10) towards said second container (6).12. Apparatus according to any one of the preceding claims, comprisingsecond motor means (18) for rotating said conveyor (10) and first motormeans (19) for rotating said first container (2), said second motormeans (18) being distinct from said first motor means (19). 13.Apparatus according to any one of the preceding claims, comprising asecond dispensing device (9) for dispensing coating material on the bulkmaterial (M) in said second container (6).
 14. Method for coating bulkmaterial, comprising the steps of: introducing bulk material (M) into afirst container (2) that rotates to promote the moving of the bulkmaterial (M); dispensing coating material on the bulk material (M)located within said first container (2); conveying the bulk material (M)from said first container (2) to at least one rotating second container(6), wherein said conveying step comprises the step of rotating arotating element (11) about a second rotation axis (X) to raise bulkmaterial (M) taken from said first container (2) from a lower height toan upper height before the bulk material (M) is transferred to saidsecond container (6), the rotation of the rotating element (11) beingindependently controllable with respect to the rotation of the firstcontainer (2).
 15. Method according to claim 14, wherein during the stepof conveying the bulk material (M) from said first container (2) to thesecond container (6), the rotating element (11) is rotated with a speedthat is lower than the rotation speed of the first container (2) andwith a direction of rotation that is concordant with the direction ofrotation of the first container (2).